Preliminary data on the agromyzid fauna (Diptera: Agromyzidae) collected during the “Our Planet Reviewed” expedition in Mitaraka (French Guiana) is provided. A total of 138 specimens representing 10 genera and 50 morphospecies are recorded. Melanagromyza Hendel, 1920 and Ophiomyia Braschnikov, 1897 were the most diverse genera with 15 and 14 species respectively, followed by Phytobia Lioy, 1864 (five species), Japanagromyza Sasakawa, 1958 and Calycomyza Hendel, 1931 (four species each), Liriomyza Mik, 1894 (three species), Nemorimyza Frey, 1946 (two species), and Agromyza Fallén, 1810, Cerodontha Rondani, 1861, and Phytoliriomyza Hendel, 1931 (one species each). Except for Liriomyza and Nemorimyza, all of these genera are recorded from French Guiana for the first time. Nearly 90% of the specimens were collected with a 6 m long Malaise trap installed for eight days on a rocky outcrop (site “savane roche 2”) during the third phase of the expedition in August 2015. Prior to this expedition, only four species of Agromyzidae Fallén, 1823 were reported from French Guiana.